2113666981 has 2 divisors, whose sum is σ = 2113666982. Its totient is φ = 2113666980.

The previous prime is 2113666937. The next prime is 2113666987. The reversal of 2113666981 is 1896663112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2045752900 + 67914081 = 45230^2 + 8241^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2113666981 is a prime.

It is a super-2 number, since 2×2113666981² = 8935176213139308722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2113666987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1056833490 + 1056833491.

It is an arithmetic number, because the mean of its divisors is an integer number (1056833491).

Almost surely, 2^2113666981 is an apocalyptic number.

It is an amenable number.

2113666981 is a deficient number, since it is larger than the sum of its proper divisors (1).

2113666981 is an equidigital number, since it uses as much as digits as its factorization.

2113666981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 93312, while the sum is 43.

The square root of 2113666981 is about 45974.6341040361. The cubic root of 2113666981 is about 1283.3511999686.

The spelling of 2113666981 in words is "two billion, one hundred thirteen million, six hundred sixty-six thousand, nine hundred eighty-one".